Failed AJAX Call -- No PHP Error Tracks

[iwato]

BACKGROUND:  I have an AJAX request that cannot find the PHP processing file for which it is looking. It is returning a 500 error in my web console.  I have checked the PHP error log for that file and can find no error.  I have also checked the error logs for the PHP files related to the requested PHP file, as well as the error log of the requesting page.  Nothing. Nothing. Nothing. And, Nothing.  I have even asked the help of my server provider.  Nothing.  Needless to say, I am at a loss.

The functionality related to this AJAX call was created many months ago, and was working fine at the time of creation.   In fact, the same functionality used to work at three different locations.   I discovered the failure while performing a somewhat casual check in search for damage from suspected hackers.  Once hacked, you do not easily forget it.  it is kind of like being raped.

QUESTION: What would be a proper strategy for troubleshooting this failure?

AJAX CALL:

		$.ajax({
			type: "POST",
			url: '.../captcha_reset.php',
			data: {dataRequest: 'requestInstance'},
			statusCode: {
				404: function() {
				alert( "Page not found" );
			}},
			success: function(jsonData) {			
				jsonObj = JSON.parse(jsonData);
				captcha_sa = jsonObj.captcha_ra;
				$('.CaptchaLabel').css('background-color', jsonObj.captcha_rc);
				$('.CaptchaAnswer').val('');
				$('.CaptchaLabel').html(jsonObj.captcha_rq);
				$('.CaptchaError').css('display', 'none');			
			}
		});

CODE from REQUESTED PHP FILE:

	if ($_SERVER['REQUEST_METHOD'] == 'POST') {
		$captcha_reset = array();
		if ($_POST['dataRequest']) {
			$dataRequest = filter_var($_POST['dataRequest'], FILTER_SANITIZE_STRING, FILTER_FLAG_STRIP_HIGH);
			if ($dataRequest == 'requestInstance') {
				require_once '.../vendor/autoload.php';
				require_once '.../select_color_pair.incl.php';
				$color_pair = select_color_pair(true);
				$ictext_color = $color_pair['text_color'];
// 				$icbackground_color = $color_pair['bg_color'];				
				require_once('.../class.imageless_captcha.php');
				$captcha_r = new ImagelessCaptcha(3, false, false, $ictext_color);
				$captcha_reset['captcha_rq'] = $captcha_r->formPhrase();
				$captcha_reset['captcha_ra'] = $captcha_r->getInt();
				$captcha_reset['captcha_rc'] = $color_pair['bg_color'];
			}		
		}
		echo json_encode($captcha_reset);
	}

Please advise.

Roddy

 

[Funce]

So I tried a couple of requests to the page mentioned and you've definitely isolated the problem code here. (Only a POST request with that payload errors)

I'd want to check if that logging system is working first.

Try introducing a syntax error and see if that comes up in the logs.

If it does, good! We know that works. We may be looking at something that is suppressing third-party code errors. (Maybe the '@' operator)

If it does not, you'll need to check your logging settings, make sure they're going to the correct location on your webhost.

[dsonesuk]

You never have more than two periods in relative links, followed by slash.

[iwato]

Hi Dsonesuk!  Happy New Year!

I purposefully wrote the paths as .../ in order to hide my file structure to the general public.  I wish it were that easy.

Roddy

 

Edited January 5, 2020 by iwato

[iwato]

Hi, Funce!  Happy New Year!

The logging system is everywhere the same.  It appears as follows:

	error_reporting(E_ALL);
	ini_set('log_errors', 1);
	ini_set('error_log', dirname(__FILE__) . DIRECTORY_SEPARATOR . 'error.log');
	ini_set('html_errors', 1);
	ini_set('display_errors', 0);

Roddy

[Funce]

Happy New Year to you too, Roddy.

And the log otherwise works with an introduced error?

[iwato]

Addendum to Initial Entry

The following is a note that I wrote to myself about the problem:

•    The Imageless_Captcha functionality is failing again.

    •    Step One:  Open overview.html
    •    Step Two:  Click on Local Search/Newsletter, Local Search/Podcast, Local Search/Q&A on the overview.html page in either the production or development folder and the result is the same. The worded number phrase does not appear, rather the phrase "Enter something here!"
    •    Step Three:  Open the WebConsole in the Network panel and discover that the PHP file:
     /home/thege0/public_html/grammarcaptive.com/devcptv18rs/_utilities/php/captcha/captcha_reset.php
         
        has not been loaded.  And, the Error Code 500 appears.
        
    •    There is no trace of a PHP error anywhere.

Roddy

 

[iwato]

Hi, Funce.  There are about five PHP error logs involved.  And, all of them contained error messages from the past that i erased.  So, I have assumed that they are working.  Just to be sure.  I will give it a try.  Just a moment.

Roddy

[iwato]

Does this look like a good syntax error?

        var_dump(goofy);

Roddy

[Funce]

Just now, iwato said:

Does this look like a good syntax error?

        var_dump(goofy);

Roddy

If it wasn't, I would be very concerned about how you're naming your defines.

[iwato]

Actually it created a white sheet.

So, I introduced purposefully the error that Dsonesuk believed that I was making accidentally, and it produced a very nice error message.  So, yes, the errors are currently being reported.  Here is the resulting error message.  It may give a clue.

[05-Jan-2020 22:06:05 UTC] PHP Warning:  require_once(.../../../../../../vendor/autoload.php): failed to open stream: No such file or directory in /home/.../captcha_reset.php on line 17
[05-Jan-2020 22:06:05 UTC] PHP Fatal error:  require_once(): Failed opening required '.../../../../../../vendor/autoload.php' (include_path='.:/opt/cpanel/ea-php70/root/usr/share/pear') in /home/.../captcha_reset.php on line 17

Roddy

Edited January 5, 2020 by iwato

[Funce]

Good, good. I want to see if any of those included files are silently erroring

Can you create a separate page that just includes them on their own, and see if that creates a 500 error?

[iwato]

I am not sure what you mean.  Each of the other pages has its own error code, just like the one that I showed above.  Therefore, if an error occurs on any one of those pages, it should appear in that pages error code that is copied into the same folder as the page.  Well, I do not not know how others do it, but it is my work flow style.

Roddy

[Funce]

I was referring to specifically these three lines. If the page errors with just these lines (and your error logging) then the error resides inside these pages.

<?php
require_once '.../vendor/autoload.php';
require_once '.../select_color_pair.incl.php';
require_once('.../class.imageless_captcha.php');

 

[iwato]

I just checked the error logs for .../select_color_pair.incl.php  and .../class.imageless_captcha.php, but could find nothing.  And, the error log that should include the errors  for .../vendor/autoload.php shows nothing.  As I did not build autoload.php, its errors do not appear in the same folder -- namely, /vendor. 

I do see what you mean.  You wanna make me work....   Just a moment.

Roddy

[iwato]

Alright.  I left the error code and the condition of the if-statement and eliminated all of the remaining processing code with the exception of those lines that you designated.  No error resulted.

Roddy

[Funce]

Now return the lines removed, one at a time, until it errors.

[iwato]

Got it.  Now I understand your madness. :-)

Roddy

[Funce]

Just now, iwato said:

Got it.  Now I understand your madness. 🙂

Roddy

It has to break somewhere!

[iwato]

Nothing. 

Nothing. 

Nothing. 

Nothing. 

Nothing. 

Nothing. 

I even tried a real var_dump that included the $dataRequest variable.  Also, you guessed it, Nothing.

Roddy

[iwato]

How about a composer update?

Roddy

 

[Funce]

1 minute ago, iwato said:

How about a composer update?

Roddy

 

Might be a good step. But you've just replaced all the lines, and the error hasn't come back? Or did it come back at an earlier step?

[iwato]

I replaced each of the lines one at a time. With each newly unveiled line I checked the functionality in my browser, and the PHP error log.  At no point was any error code exhibited.  I even reset the line that I had previously commented out. Nothing.

I am currently researching how to update composer.  The number of composer.json files that I have is absolutely amazing.  They are everywhere and mostly places where I never have been and have no desire to go.

OK.  I have just updated with php composer.phar 

Roddy

[Funce]

Oh! I see. Can you instead look for 200 vs 500 response code behaviour, and try it again?

[iwato]

Yes, the file is now reported as loaded, and WebConsole is now reporting a Javascript error, but I am not sure from where.  Above is the only use of the JSON.parse command in the entire calling file.

success: function(jsonData) {			
    jsonObj = JSON.parse(jsonData);
    captcha_sa = jsonObj.captcha_ra;
    $('.CaptchaLabel').css('background-color', jsonObj.captcha_rc);
    $('.CaptchaAnswer').val('');
    $('.CaptchaLabel').html(jsonObj.captcha_rq);
    $('.CaptchaError').css('display', 'none');			
}

This is the error message:

SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

Wow!  And, just when I thought things were looking bleak. :-)

Roddy